1. Field of the Invention
The present invention relates to a winding method and device for photo film and a photo film carrier. More particularly, the present invention relates to a winding method and device for photo film, and a photo film carrier in which the photo film can be prevented from being scratched or damaged.
2. Description Related to the Prior Art
There is a photo film cassette of the IX240 type which contains a roll of photo film, such as negative photo film. After the photo film is developed, the photo film is wound back on a cassette spool the photo film cassette, and accommodated in the photo film cassette. To print an image frame in the photo film to photographic paper, thermosensitive recording material or the like, a photo film carrier is used for setting the photo film cassette, from which the photo film is drawn out in the photo film carrier. The photo film from the photo film cassette is fed intermittently, to set the image frame in a position for image reading or image printing. In the reading or printing position, light is emitted by a light source and applied to the photo film at a predetermined time. Light transmitted by the photo film is obtained for reading or printing the image frame.
However, the photo film is involved with curls to a considerable extent, as the photo film is preserved in the photo film cassette in a form wound about the cassette spool. Portions of the photo film drawn from the photo film cassette are likely to entwine one another. Failure in smooth rewinding to the photo film cassette is likely to occur after printing operation with the photo film. The photo film is likely to have scratches, flexing, and other damages. To solve such problems, JP-A 8-006168 (corresponding to U.S. Pat. Nos. 5,683,052, 5,718,393 and 5,820,054) discloses a type of the photo film carrier, which has a winding chamber where a winder shaft winds the photo film from the photo film cassette. To wind the photo film, the winder shaft is rotated at a circumferential speed higher than a feeding speed of the photo film. The photo film is wound about the winder shaft in application of regularized tension to the photo film.
However, the photo film carrier of the prior art has a problem in that at least one turn of the photo film must be wound about the winder shaft before the turn of the photo film can be tightened. Surfaces of the photo film are rubbed by one another, and scratched or damaged. This problem is typically serious if the photo film is 135 type, because the photo film does not have a leader but has the image frame starting directly from a front end of the photo film.
In view of the foregoing problems, an object of the present invention is to provide a winding method and device for photo film, and a photo film carrier in which the photo film can be prevented from being scratched or damaged due to contact between photo film portions.
In order to achieve the above and other objects and advantages of this invention, a winding method for photo film is provided, in which the photo film is introduced to a winder shaft through a feeding path. A leading end of the photo film is tightly fitted on the winder shaft by pressing the photo film from the feeding path, to prevent the leading end from being loose at the winder shaft when a second turn portion of the photo film comes to contact the leading end after substantially one rotation of the leading end.
Also, a winding device for photo film is provided, and includes a rotatable winder shaft. A feeding path introduces the photo film to the winder shaft. A leading end guide plate is curved in an arc shape at a predetermined interval to the winder shaft, for receiving a leading end of the photo film having reached the winder shaft from the feeding path, to guide the photo film toward the winder shaft by bending in an arc shape. A tightening guide mechanism is curved in an arc shape, for tightly fitting the leading end on the winder shaft by pressing the photo film from the leading end guide plate, to prevent the leading end from being loose at the winder shaft when a second turn portion of the photo film comes to contact the leading end after substantially one rotation of the leading end.
Furthermore, a feeding mechanism feeds the photo film at a predetermined introducing speed V1 through the feeding path. A shaft drive mechanism rotates the winder shaft in a winding direction at a predetermined circumferential speed V2 higher than the introducing speed V1, whereby the guiding mechanism eliminates looseness from the leading end.
The winder shaft includes a core. A frictional lining member has a tubular shape, for covering the core, to capture the photo film frictionally.
The tightening guide mechanism includes a tightening guide plate. A bias member biases the tightening guide plate toward the winder shaft, to press the photo film.
The tightening guide mechanism further includes first and second press rollers, secured to the tightening guide plate, for pressing the photo film toward the winder shaft.
The tightening guide mechanism further includes first and second grooves, formed in the tightening guide plate, extended in an axial direction, for supporting the first and second press rollers in a rotatable manner, and at least portions of the first and second press rollers protrude from the first and second grooves.
The shaft drive mechanism includes a motor for rotating the winder shaft in the winding direction by rotating forwards, to wind the photo film about the winder shaft. A torque limiter is secured between an output shaft of the motor and the winder shaft, for causing the winder shaft to slip from the output shaft if load to the photo film becomes over a reference level in winding the photo film, and for transmitting rotation of the output shaft to the winder shaft.
The shaft drive mechanism further includes a one-way clutch, secured between the output shaft of the motor and the winder shaft, for transmitting rotation to the winder shaft when the motor rotates forwards, and for making the winder shaft free from the motor when the winder shaft rotates in an unwinding direction, to allow unwinding the photo film.
The one-way clutch is secured between the torque limiter and the winder shaft.
According to another aspect of the invention, a photo film carrier adapted for reading or printing an image frame in photo film is provided. The photo film carrier includes a loader unit for being loaded with the photo film, a winder unit for winding the photo film from the loader unit, a feeding path for passing the photo film from the loader unit to the winder unit, and an opening, formed in the feeding path, for external access to the photo film for reading or printing of the image frame. In the photo film carrier, the winder unit includes a rotatable winder shaft. A leading end guide plate is curved in an arc shape at a predetermined interval to the winder shaft, for receiving a leading end of the photo film having reached the winder shaft from the feeding path, to guide the photo film toward the winder shaft by bending in an arc shape. A tightening guide mechanism is curved in an arc shape, for tightly fitting the leading end on the winder shaft by pressing the photo film from the leading end guide plate, to prevent the leading end from being loose at the winder shaft when a second turn portion of the photo film comes to contact the leading end after substantially one rotation of the leading end.